A nested case-control study of end-stage renal disease (ESRD). Cases of treated ESRD who began treatment a median of 15 years after donating serum will be studied offering a rare opportunity to study serologic risk factors which substantially precede the onset of ESRD. The risk factors examined will include serum lipids, antioxidants, and nitric oxide metabolites. During this year we matched the majority of the cases and conducted the chemistry and antioxidant analyses (n = 101 cases and matched 200 controls). During the next year we will complete the additional cases and controls (approximately 20 cases and 20 controls). This will be followed by data analysis and manuscript writing.